Paper container blank



March 14, I

H. LEHMANN PAPER CONTAINER BLANK Filed March '7, 1939 2 Sheets-Sheet 1 a V W T fin/e2 Z or j (M/ 4 man/z Patented Mar. 14, 1944 PAPER CON TAIN ER BLANK Harry Lehmann, Dusseldorf, in the Alien Property Germany; vested Custodian Application March 7, 1939, Serial No. 260,391

Germany March 7, '1938 3 Claims. (01.229-37) The invention relates to improvements in paper containers having bellows-like folded closures and to improved means for producing such containers, whereby tight sealing of the folded closure is achieved.

The paper containers, formed according to the invention, are characterized by an especially tight and safe folded closure, since every space existing between adjacent layers of the closure is closed by a folded adjacent overlapping end. In paper containers which are impregnated with paraflln wax or the like, this arrangement is especially well suited to be secured by heat-sealing. Further, according to the inventionthe heat-sealing of the folded closure can take place in such a way that the folds of the closure are strongly pressed together and at the same time is heated to a temperature slightly below the melting point of the impregnating material only enough heat need be used to make the impregnating material tacky and adherent to similar material under the pressure used. Complete softening or liquefaction of the impregnating material is thereby avoided, and dripping of liquid impregnating material into the container to be sealed is precluded. Formed as disclosed herein the sealed folded closure will not open up under the influence of the tension in the paper when the closing pressure is released, because of the tackiness of the impregnating material which has been heated only slightly, in,-' stead of being liquifled.

For the production of paper containers according to the present invention which flare conically toward the top, only such blanks have to be con sidered in which panels, which eventually form the upper rim oi the container, are bounded by a. substantially straight line extending over half around the rim. In a blank for a container flarng toward its top, and whose folded closure opens ;o a rectangular or polygonal aperture, in accordtnce with the inventiomthe portion of the blank vhich later forms the upper rim of the container s bounded by a substantially straight line which ixtends at least around three sides of the closure.

In the appended drawings a paper container, 9. dank used in its production, and the method of ealing the container are illustrated without inention to limit the invention precisely thereto.

In the drawings:

Figure 1 illustrates the usual arrangement of ne known blanks in the paper web from which my are cut out,

Figure 2 illustrates the arrangement of blanks ccording to the invention in a paper web from hich they are cut out,

, folded closure which Figure 3 illustrates the upper part of a paper container according to the invention with fully opened closure,

Figure 4 illustrates the partly closed closure, v

Figure 5 illustrates the same paper container with flat folded closure,

Figure 6 illustrates the same paper container after folding the upper rim of the flat folding closure, v

Figure 7 illustrates the paper container with pressure and heat-sealed folded closure,

Figure aillustrates in an enlarged transverse section through the closure taken on the line A-B of Figure 6.

For the production same container with of paper containers with a opens to a square cross-section aperture and which is bellowsfolded the blanks are cut out of a paper web in a known manner, as illustrated in 1. Thepoints U'I'WV constitute in the formed container the corners of the square-shaped mouth. In the cutting-out of the blanks very little waste is caused. The waste caused for a single blank consists only of the three pieces a, b, c marked by dotted lines in Figure 1 of the drawings.

According to the present invention the blanks are formed as shown in Figure 2. The waste is thereby considerably reduced because the waste for a single blank involves only the pieces a, b and c. It is obvious that the waste pieces a and b' are considerably smaller than the waste pieces a, and b of Figure 1. The container blank is enlarged to such an extent that it extends over the hitherto existing lines TU and WV respectively, as far as the lines TXY and WZY respectively thereby utilizing portions of the paper formerly wasted. From such blanks the paper containers are formed which are shown in Figures 3 to 8. The upper rims of prior containers are bounded usually by the lines TUVW which extend parallel to the bottom, but the rims of the paper containers shown in Figures 3 to 8 are extended above the mentioned lines TUVW up to the upper parallel to the and W2 rise diagonally whereby at the fourth the flap XYZ. At this of the container body 2 adjacent paper layers-overlap each other stepwise as shown in Figure 5. The front side having. the upper edge 'I'W is overlapped by the adjacent parts ofthe bellows-like folding, since the upper edges TR. and WS extend above the edge TW. These edges are overlapped by the edges RS and SZ of the next paper layers, above which the flap XYZ projects which is formed at the fourth or back side of the container. Figures 6 to 8 show that the overlapping parts of the folding closure, which extend above the lowest edge line TW, are folded downagainstthe part of the flat folded closure below the line TW. The slit adjacent to the front part ofthe container is covered by the folded edge portions TR and WS of the adjoining folded parts of the container wall. The next overlapping is formed by the folded rims RX and S2. The slit which is between the fourth container wall and the bellowslike folded wall parts is overlapped by the folded flap XYZ. The position of the folded parts and particularly the stepwise overlapping thereof is illustrated by Figure 8, in which it is seen that no folded flap is required to cover more than one slit, and that as a result complete closing of each slit is achieved.

For security, a clip of metal, Bakelite, Celluloid or any other suitable material can be pressed in a known manner over the folded closure described. In paper containers which are impregnated with paraffin or the like, the formed closure can also be secured by heat-sealing. For 4 this purpose the folded closure is strongly pressed between jaws and at the same time heated to a temperature which is slightly below the melting point of the paraffin or the like. Under the simultaneous influence of pressure and heating, the parafiin becomes pliable so that it fills the slight roughness and unites the paper layers pressed against each other. Preferably, the

, pressing jaws are formed in a known manner in such a way that, as illustrated in Figure 7, the

closure is provided with longitudinal wave-like lines or the like. Heat-sealing is especially effective in a paper container in-accordance with the invention. The front part of the paper container which ends in the edge TW and the adjacent bellows-like folded wall parts are not only kept together .by heat-sealing the inner face of the mentioned front part of the paper container, but also by heat-sealing the folded overlapping parts ending at the edge lines TR and WS. In similar manner the closure is further secured against coming open due to the tension of the paper and other stresses by the heat-sealing of the stepwise overlapped parts, the edges of which are defined by the lines RX, SZ and XYZ.

The methods according to the invention are especially eifective when dealing with paper containers, which are folded E E shaped They may, however, also be employed advantageously in other kinds of folding, for example in such cases in which several bellows-like folds are formed immediately adjoining each other.

For more specific definition in the claims, the upright sections defining the container proper will be referred to as walls, while the sections rising above the bellows-top closure will be defined as panels.

From the foregoing it is obvious that my invention is not restricted to the exact embodiment shown in the drawings but is broad enough to cover all structures coming within the scope of the annexed claims.

I claim:

1. A one-piece blank adapted to be folded to form the body of a container having a heliumlike closure at the top and downwardly converging sidewalls, said blank having four spaced converging fold lines defining a tapered mid panel and two adjacent tapered side panels on each side thereof, said panels increasing in length from the mid panel to the side panels and the panels converging toward the bottom forming end of the blank, the blank on the closure forming end terminating in a straight line, said blank when folded to form the body of the container having its side edges brought together to form a seam medially of one side.

2. A blank for a paper container enlarging on al1 sides and tapering from its bottom end to a bellows-like form at its upper end and providing a foldable closure for the container, said blank being scored to provide a plurality of tapered side panels and the bellows-like closure, the edge of the blank eventuating in the upper rim of the container being straight and extending substantially across all the panels, said straight edge portion terminating just short of the outer edges of the outer panels.

3. A paper blank adapted to be folded to form a container tapering upwardly from its bottom to a bellows-like form providing a foldable closure for the container, the blank having converging fold lines defining a mid panel, side panels on opposite sides of said mid panel, and the closure for the container, the upper edges of said mid panel and said side panels constitutingthe upp edge of the container, said upper edges be formed to provide, in the blank, 9. straight edge extending across the mid panel and the two adjacent panels,

HARRY LEHIWANN. 

